jimmydd7 > i'm assuming you are talking about the sunset city one. it's really simple my friend, just put a paper texture on the top of everything and put it overlay, softlight or whatever layer works the best for you.

Much love.
Those are some really really nice matte paintings. I especially like how you often give the skies a very colorful appearance. The reds, blues and grays lead to some very nice scenes.
Keep up the nice work.